1. Field of the Invention
The invention is in the general field of improved methods of pumping viscous hydrocarbons through a pipe, such as well-bore or a pipeline.
2. General Background
The movement of heavy crudes through pipes is difficult because of their high viscosity and resulting low mobility. One method of improving the movement of these heavy crudes has included adding to the crude lighter hydrocarbons (e.g. kerosine distillate). This reduces the viscosity and thereby improves the mobility. This method has the disadvantage that it is expensive and the kerosine distillate is becoming difficult to obtain.
Another method of improving the movement of these heavy crudes is by heating them. This requires the installation of expensive heating equipment and thus is an expensive process.
Still another method of moving heavy crudes through pipes uses oil-in-water emulsions which use surfactants to form emulsions.
U.S. Pat. No. 3,943,954 teaches lowering the viscosity of a viscous hydrocarbon by adding an aqueous solution containing an anionic surfactant, such as sodium tridecyl sulfate, together with a guanidine salt and optionally with an alkalinity agent and/or a nonionic surfactant such as a polyethoxylated alcohol.
I have found that use of an aqueous solution containing a combination of an ethoxylated alkyl phenol and a low molecular weight alkaryl sulfonate provides better viscosity reduction than use of either material alone. Moreover, I have found that use of a guanidine salt is not necessary. I have obtained results equal to, or even better, when the combination of ethoxylated alkyl phenol and low molecular weight alkaryl sulfonate is used without the guanidine salt.